Waterproofing composition



Patented Get. 20, W36

barren orrice WATERPROOFDTG COIWPO SITION poration of Illinois No Drawing.

13 Claims.

Thisinvention relates to a new waterproofing composition and a method of waterproofing cellulose and protein fibrous materials such as silk, wool, paper, cotton and the like.

- It has now been discovered that a superior waterproofing material may be prepared by reacting casein with aluminum formate, whereby a water-soluble reaction product, apparently in the nature of an addition product, is produced. This reaction product has the property, when applied to fabricmaterial, of producing, apparently by reaction with the fabric, a waterproof coating of improved character. The reaction of casein and aluminum formate to produce a soluble product is particularly remarkable in View of the fact that other aluminum salts are widely used for the purpose of fixing casein in an insoluble form. That the formate should have such a dissolving efiect is further remarkable in that formic acid and. formaldehyde are widely used for the purpose of hardening casein.

While casein and aluminum formate have heretofore been used separately as waterproofing agencies, the new composition not only produces 25 a greater degree of wate'rproofness, but can be used for this purpose in a much more dilute solution than either of the other products, and at the same time the results are better than obtained with casein or aluminum formats alone 30 or used in successive stages. In accordance with this invention, to 50% aluminumformate is used with 90 to 50% of casein, the products being preferably milled together until in the form of a fine powder. They are then added to hot 35 water and digested at a moderate temperature until solution is complete. The solution so obtained may be used as a bath for the immersion of cellulose, wool or silk materials, which are treated in the bath for a period of five minutes 40 to one hour, depending upon the nature and condition of the material to be treated. For example, loose cellulose fibres will not generally require more than five minutes for treatment, whereas a pressed paper ora tightly woven fab-.- ric may require a considerably longer period.

As an example of the invention, 7 parts of casein and 3 parts of aluminum formate are milled together to a fine powder and added to a sufiicient amount of hot water to give a solution 50 of 10 to concentration. This mixture is preferably maintained at about 75 to 80 C. for about one-half hour, after which it is cooled to about 60 C. and held at this temperature until the casein is dissolved and the aluminum formate-caseln complex developed. This normally Application March 29, 1935, Serial No. 13,785

willtake about one hour. It is preferred not to heat the mixture above '7 5 C. for a period longer than thirty to sixty minutes, inasmuch as such heat treatment appears to cause a partial decomposition and reduces the waterproofing ability of the complex.

While 10 to 50% of aluminum formate may be used, it is preferred, primarily for economic roe-- sons, to use.25 to 35%, which is a sufiicient amount to cause ready solution of the casein. Smaller amounts-of aluminum formate require a longer period for solution. For example, with 30% of aluminum formate, a solution can normally be prepared in one to two hours, whereas with 10 to ofaluminum formate, the period required is several times longer.

The concentrated solution prepared by the original reaction may then be diluted with warm water until the concentration of the complex is waterproof coating understood. Both reactions appear to involve chemical changes, as distinguished from mere mixtures or coatings, however.

The casein-aluminum formate complex may be produced in dryfiaked or solid form by carefully evaporating a solution thereof to dryness in a suitable drier. If the concentrated solution of the complex is cooled to room temperature, it produces a gel form in which the material may be marketed if desired.

As a specific example of the invention, a powdered mixture of '70 parts of casein and parts of aluminum formate are introduced into 800 to 1000 parts of water at 75 to 80 C. and held at this temperature for approximately twenty minutes to effect the solution of the aluminum formate, after which the temperature is reduced to about 55 to 60 C. and maintained for approximately one hour or until the casein is completely dissolved and a clear solution obtained. This strong solution is then diluted with water at 60 C. to give a solution of approximately 1 to 3% concentration. A 2.5% solution was prepared in -the above manner and used as a bath at a temperature of 60 C. for treating samples of paper,

cotton-cloth and wool-cloth. After periods vary-' ing from ten minutes to an hour, the pieces were removed from the bath, the excess solution drained off and the pieces dried at a temperature of 60 C. To test the waterproof qualities, the samples were made into bags and filled with water. After twenty-four hours, no water had leaked through and the bags were perfectly dry on the outside.

Concentrations as low as 1 appears to result in a satisfactory waterproof material, while on the other hand concentrations higher than 3% no not appear to result in any increase in efiectiv-eness.

Where aluminum formate orcasein alone has been used as a waterproofing material, concentrations of 5 to have beenrequired.

It has further beendiscovered that where it is desirable to produce a waterproofed fabric of superior softness and pliability, for instance, in the case of cotton or undyed cloth, the fabric may be treated with a soap solution either before or after the waterproofing treatment. Preferably, the treatment is made before the waterproofing step.

Fabrics waterproofed by this process are permanently waterproof and maybe subsequently washed in warm water and soap without detrimental eifect.

It is preferred that the fibres be given the waterproofing treatment prior to the use of any sizing materials. Where the solution of the casein-aluminum formate complex is to be kept for some time, a. small proportion of borax (NazBrOw) may be included as a preservative. This proportion is normally less than 1%.

The foregoing detailed description has been given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, but the appended claims should be construed as broadly as permissible, in view of the prior art. v

What I claim as new, and desire to secure by Letters Patent, is:

1. As an article of commerce, a water-soluble caseinous waterproofing reaction product of casein and aluminum formate.

2. As an article of commerce, the caseinous re action product obtained by reacting 10 to 5 0% aluminum formate with casein in water.

3. As an article of commerce, the caseinous reaction product obtained by reacting 25 to 35% aluminum formate with casein in water.

4. The method of dissolving casein, which comprises admixing casein with aluminum formate, and digesting the mixture in hot water for a short period. I

5. The method as set forth in claim 4, in which the proportion of water, casein and aluminum formate is about 6 to 10 parts water to 1 part solids, and in which the temperature is maintained at about 70 to 80 C. for a period of the order of twenty to sixty minutes, and the temperature isthen maintained at 50 to 60 C. until the casein is dissolved.

6. As the composition of matter, an aqueous jelly comprising 6 to 10 parts water and 1 part of a casein-aluminum formate complex.

7. The process of waterproofing a cellulose or protein fibre which comprises, immersing the fibre in a solution of a casein-aluminum formate complex and subsequently drying the fibre at a temperature as high as 60 C. F

8. The process of waterproofing a cellulose or protein fibre which comprises, reacting the fibre with a casein-aluminum formate complex to produce a waterproof surface thereon.

9. The process as set forth in claim 7, in which the fibre is treated in the bath at 50 to 60 C.

for a period of five minutes to an hour.

10. The method as set forth in claim 8, in which the fibre is treated with a soap solution prior to treatment with the casein-aluminumformate complex.

- 11. As an article of commerce, a composition of matter consisting of powdered casein and aluminum formate, the aluminum formate comprising from 10 to 50% of the casein.

12. As an article of commerce, a. waterproofed cellulose or protein fibre having thereon, a reaction product of the fibre and a casein-aluminum formate complex.

13. As an article of commerce, a fabric having the waterproof characteristics produced by immersion of the fabric in a solution of a. caseinaluminum formate complex and subsequent drying of said treated fabric at an elevated temperature. I s

HANS B. GO'IILIEB. 

